This invention relates generally to orthopedic implants possessing drug-eluting or drug-diffusing capability. More particularly, the invention is for an anterior spinal plate having such capability.
Numerous orthopedic implants, including spinal implants such as anterior spinal plates, are known to possess adherent coatings, layers or films containing one or more drugs, e.g., medicaments, therapeutics, biologicals or other bioactive substances, etc., such as antimicrobials, antibacterials, antibiotics, antifungicides, anti-inflammatories, and the like. Following the installation of such an implant in the body, the drug(s) present in the coating elutes therefrom over time into the region of surrounding tissue to achieve the desired drug actions(s).
One of the problems encountered in the manufacture of an orthopedic implant possessing a drug-eluting coating involves the sterilization of such a device. The more economical methods of sterilization utilize steam under pressure, e.g., as produced in an autoclave. While such sterilization methods are known to be highly effective, they are subject to a major disadvantage where thermally sensitive drugs are concerned and therefore are of limited use. While the conventional use of sterilizing radiation or a sterilant gas such as ethylene oxide can reduce the risk of damaging or partially to completely inactivating the drug component(s) present in the coating component of an orthopedic implant, such sterilization methods are relatively expensive. While it is possible in principle to apply a drug-containing coating to a pre-sterilized implant under sterile conditions followed by the sterile packaging of the coated implant, such an approach to providing a packaged sterile orthopedic implant, which avoids subjecting the drug(s) contained in its drug-eluting coating to thermal decomposition or deactivation, is largely an impractical one.
Therefore, what is needed is a drug-eluting cover that can be applied to an implant in vivo or in vitro where the drug-eluting cover can be sterilized separately from the implant and configured to fit a variety of implants. The present invention provides such a device and is described in further detail below.